Broadback wrote:
Helen Deborah Vecht wrote:
Alan typed

Also tried a new stanley blade, that dosn't work.

Any advice appreciated.

WD40 and leave for a few hours.

We were advised petrol when we had this problem a while ago, on wooden
windows. It is a b*****.

Word of warning for all: masking tape (and Micropore) polymerise in UV
light.
Masking tape should never be left on for more than 24 hours damn it...

If masking tape gets wet it is very difficult to remove. The only thing
I have found to remove it is acetone, also known as propatone. This is
the same as nail varnish remover, though buying it in that form is very
expensive. If you have a friendly fibre glass worker near you they may
be willing to fill a bottle for you.

Search the archives. This has come up quite often. They suggest WD40 here
http://www.duckproducts.com/tips.asp?Sub=2&Cat=1